As far as I know, there is not a signal repeating KFDF-LD in the northern half of the market at this time. KFFS-CA is not operating digitally.
Now, according to filings with the FCC, some of the transmitters such as KKAF-CD 33 in Siloam Springs are on the air, but I have heard nothing to indicate that to actually be the case.
I suspect you are correct that you will not be finding RTV over the air at this time. I am certain KFFS-CA will be converted in the future, but I have no information about a time frame for it.